Latest exoplanet discovery is a virtual CLONE of Earth

Right size, right star, right orbit

Common Topics

Astroboffins poring through data from NASA's Kepler telescope have spotted what they think might be the most Earth-like planet yet discovered.

The object has a radius 1.5 times that of Earth, which lumps it into the class of extrasolar planets known as "super Earths." That's not so unusual, in and of itself; scientists estimate that about 25 per cent of known star systems feature similarly sized worlds. What makes this one special, however, are all of the other ways in which it resembles our own planet.

That is, not only does the suspected planet resemble Earth, but the star it orbits is also comparable to our own, and the planet is orbiting it at just the right distance to allow the presence of liquid water, and therefore – just possibly – life.

Specifically, the planet is orbiting its star at an average distance of 70 million miles. Earth orbits the Sun at a distance of 93 million miles, on average, but the newly discovered planet orbits a star that's slightly cooler than our own.

The new planet also orbits its star at a rate similar to that of Earth. Its year is 242 days long – slightly longer than Venus's 225-day year but shorter than our own 365-day one. By comparison, previously discovered super Earths generally have orbits of 150 days or less.

This latest Earthy object was just one of a batch of 461 new planet candidates that NASA scientists announced on Monday. Of those, four had characteristics that could make them "potentially life-bearing," but only one shared so many traits with Earth.

Mind you, some of this is just conjecture. More work needs to be done to verify that the object is in fact a planet. Right now, it has been dubbed only KOI 172.02, for "Kepler Object of Interest."

And even if it is confirmed to be a planet, it's still too early to know whether it has other characteristics that would allow it to play host to life similar to that on Earth, such as a rocky surface or an oxygen-rich atmosphere. Still, researchers are hopeful.

"It's a big deal. It's definitely a good candidate for life," Mario Livio of the Space Telescope Science Institute in Baltimore told SPACE.com. "Maybe there's no land life, but perhaps very clever dolphins." ®